In U.S. Pat. No. 3,658,364, computer print-out paper is disclosed as having a number of spaced stiffeners for the back face thereof so that the stiffeners will increase the stiffness of relatively lightweight paper. The stiffening of the paper will allow it to be moved through high-speed computer printing equipment, such as IBM 3211 and N1-1403 Printers, and emerge from the equipment and to be quickly and easily re-fan-folded into a neat stack.
Computer paper is provided with a plurality of transverse fold lines which divide the paper into sheet sections of substantially the same size. As the paper emerges from rotary printing equipment, it passes through a fan-folding mechanism which causes the paper to be folded along the fold lines and to fall onto a stack formed of superimposed sheet sections. Lightweight computer paper could not ordinarily be properly re-fan-folded in the absence of the stiffeners because of its not being stiff enough to avoid bunching or rolling as it emerges at high speed from the computer printing equipment.
It has been found that the re-fan-folding of the paper emerging from high speed computer printers can be enhanced if at least certain of the sheet sections are not allowed to droop or bend downwardly as they are suspended from about by succeeding sheet sections and as they approach the stack of sheet sections in advance thereof. Thus, it is desirable that resistance to downward bending of the sheet sections be provided therefor to achieve optimum re-fan-folding.
Thus, the advantages of using relatively lightweight paper with stiffeners include the fact that this type of paper is less expensive than relatively heavier weight paper; the lightweight paper takes up less space in shipping cartons; a greater amount of lightweight paper can be accommodated in a shipping carton so that a greater supply of apper is available to increase the operating time of the computer printing equipment; and the lightweight paper requires less storage space than does relatively heavier weight paper. Fifteen pound computer paper, for example, as compared with twenty pound computer paper, reduces handling weight and shipping costs.